A new Authentication object is created by this class comprising the request Authentication
object's principal, credentials and the GrantedAuthority[]s returned by the
RemoteAuthenticationManager.

The RemoteAuthenticationManager should not require any special username or password setting on
the remoting client proxy factory to execute the call. Instead the entire authentication request must be
encapsulated solely within the Authentication request object. In practical terms this means the
RemoteAuthenticationManager will not be protected by BASIC or any other HTTP-level
authentication.

If authentication fails, a RemoteAuthenticationException will be thrown. This exception should
be caught and displayed to the user, enabling them to retry with alternative credentials etc.

a fully authenticated object including credentials. May return null if the
AuthenticationProvider is unable to support authentication of the passed
Authentication object. In such a case, the next AuthenticationProvider that
supports the presented Authentication class will be tried.

supports

Returns true if this AuthenticationProvider supports the indicated
Authentication object.

Returning true does not guarantee an AuthenticationProvider will be able to
authenticate the presented instance of the Authentication class. It simply indicates it can support
closer evaluation of it. An AuthenticationProvider can still return null from the
AuthenticationProvider.authenticate(Authentication) method to indicate another AuthenticationProvider should be
tried.

Selection of an AuthenticationProvider capable of performing authentication is
conducted at runtime the ProviderManager.